Such machines are, of course, known in the prior art to a large extent and they are used in great variety of cases. Such injection moulding machines are often also used for producing preforms which are subsequently subjected to a blowing process. In the production of large-volume beverage bottles of plastic material, for example, it is known to produce a preform in an injection moulding machine and to let said preform cool down so that it can then be given its final shape after an appropriate thermal pretreatment directly at the beverage-manufacturing firm. In this connection there are, however, also solutions in the case of which the preform is removed from the injection moulding machine and supplied to a conveyor means passing with said preform a large number of intermediate processing steps, such as e.g. crystallization of the thread area for the screw top. Finally, a heat treatment step is carried out prior to the actual blowing process. These processes known in the prior art have the great disadvantage that they are specially adapted to the production of beverage bottles and that this type of device has not gained general acceptance for producing other injection-moulded/blow-moulded parts.